Hello, Would like to know how many BTUs (for 1 wallmount system)would I need for two floors of 690 sqfeet (each floor). The Unit will be on the 2nd floor in the middle between 2 bedrooms and a washroom (over washroom door facing master bedroom). It will be a dual split system. ------------------------------------- Also would like to know which is a safe reliable cost efficient brand, example of wall mounted (split systems) air conditions I've heard of: Fujitsu (they give 10 years warranty parts and labour) Mitsubishi (6 yrs parts and labour however been making them longer) Daikin (6 yrs parts and labour) Igloo York Carrier Grey All about the same price... ----------------------------------- Finally, is it better to get a dual system (with heat pump), from my understanding they are almost the same price and the advantage is that it has a variable BTU which may save some $$. Since the heat pump will be at the higher level then it wont heat as much however it is coming at about the same price. Then again more electronics in a system more chances of malfunctioning sooner? Thank you, Stelios

"However, it seems really weird to simply have a tube practically hanging in mid-air to connect the two." The power feed, control lines, and refrigeration lines are not normally buried or otherwise protected beyond using materials safe for exposure to weather and sun. The distances are normally very small, and the placement of the unit adjacent to the structure discourages walking between them. I try to place the disconnect directly above the location the refrigeration lines exit the building, and often fasten the thermostat line top the outside of the liquid tight with tie wraps. It is the most easily damaged of the lines, and the entry is normally adjacent to the power entry. transitioning from the building wiring to the outside wiring is not a big deal since a disconnect is required near the condenser. If you feed the power line into the disconnect from the back of the enclosure there is no exposure of the feed wiring outside the building at all.

Hi, Ron. It seems the cause of trouble was found. Close to your guess, a Staple. Today, I had another electrician for 2nd opinion. And after his visit to attic, he said the wire is ok and AHU is the cause. Wired! So we went to main service panel and found the wire is open, no short! Then I ask him to try breaker test and the breaker tripped! Wired again! And he mentioned the receptacle might be a cause and asked me pay $$$ for further tracking. So, I paid him for today's visit and he left. I went to the attic, and unwired the receptacle and did short test on the two troubled wires. Open! Wired the receptacle. Then I found a staple right under the junction box and check the wire under the staple. The jacket of wire was not damaged but the wires feel little play. So, I wiggle the wire a little bit while two test probes on the wires. Open-short-open-short-... Ah! I set the wire in open position and went to the main service panel and tested breaker. It stayed! I think the wires were damaged during one of previous works, maybe someone bent it too hard during work, the house is 20+ yrs old, but anyhow managed to maintain the contact until 3 days ago. I'll call home warranty company to arrange a work to fix it tomorrow. No tear down of drywall! However, I still curious about one thing. Why the tester showed 'Open' while the breaker tripped due to short between two wires under the staple? Maybe they have different ways of working on short condition. Maybe someone have answer. Anyway, thank you Ron again for your comments when I desperately needed help. Hope you have a wonderful holidays. Kihong

building2017 wrote: ... - What are the silencers I have read about and how do they work/would they work here? These are like giant truck mufflers, except designed for various diameter ducts. They have low pressure loss (forget the value but it is a lot less than baffles). Fantech is the source. - Any benefit re:sound to using two smaller liners instead of one big one and only using one at a time when using only one side of stove? Or is this magnifying the cost for no good reason other than sound? (Because I'm assuming I'd then have two runs up and out and two things on the roof because they wouldn't combine to avoid a turn and to ensure proper function? If only one side were run at a time, then MUA costs could be lower, but where code requires MUA, I am willing to bet a donut that the AHJ will demand an MUA system that can handle both at once. In theory, the sound reduction will be only 3 dB less. Also, when using the central burners, you will still need both systems for capture and containment. Well, I guess three things on the roof then with the MUA. While commercial systems mostly use roof MUA entry, and I use roof MUA entry, the options for residences are wide open and may include side of house entry, or entry into a basement that has an air path access to the kitchen.